Symptoms
When trying to access the topics page in the admin site, a server error "Object reference not set to an instance of an object" is thrown.
Cause
This can be caused by not having a locale set up in the ASPDNSF admin site that matches the locale in the web.config.
Solution
Locate the 'culture' and 'uiculture' attributes in the <globalization> node in the web.config file (near the bottom). Verify that the value set for those attributes is a valid .NET locale, and that the locale exists in the ASPDNSF admin site on the Locale Settings page.